1. Field of the Invention
Present invention relates to the destruction, elimination and/or inactivation of pathogenic microbes in biological fluids. In particular, it relates to antimicrobial photodynamic laser therapy method and device to eliminate pathogenic microorganism in biological fluids such as blood and blood products.
2. Invention Disclosure Statement
The spread of blood borne diseases resulting from transfusion of contaminated blood or blood product is recognized as a major medical health problem. Blood is most commonly donated as whole blood by inserting a catheter into a vein and collecting it in a plastic bag (mixed with anticoagulant) via gravity flow. Thus collected blood is then separated into components. Aside from red blood cells, plasma, and platelets, the resulting blood component products also include albumin protein, clotting factor concentrates, cryoprecipitate, fibrinogen concentrate, and immunoglobulins (antibodies). Red cells, plasma and platelets can also be donated individually via a more complex process called aphaeresis.
The importance of blood transfusions is widely known, especially in cases of people who suffer major trauma such as car accidents or in many surgeries that could not be performed without transfusion support. Without enough blood in blood vessels due to acute or massive blood loss there is not enough pressure to push new blood to the tissues, causing organ death because of lack of oxygen. Blood transfusions may also be used to treat severe anemia or thrombocytopenia caused by blood diseases. Another condition requiring frequent blood transfusions is people suffering from hemophilia or sickle-cell disease. Depending on the disease requirements, whole blood or blood products such as fresh frozen plasma, platelet concentrates, red blood cell concentrates and others should be transfused. In any case, to prevent a hazardous recipient's immune reaction transfused blood should be compatible with the components of the recipient's body.
Blood transfusions can be life-saving but, as with any treatment, there are risks involved. Many viruses, parasites, bacteria and/or toxins may be present in human blood and if contaminated blood or blood products are not efficaciously inactivated or the contaminants are not properly eliminated prior to blood transfusion this may cause infectious diseases with high mortality rates. There is a risk that a given blood transfusion will transmit a viral infection to its recipient. The risks of acquiring hepatitis B virus (HBV), Human Immunodeficiency virus (HIV) or hepatitis C virus (HCV), via blood transfusion are a major health threat even in developed countries like the U.S.
Bacterial resistance against antibiotics makes an infection much harder to treat. Higher doses or stronger drugs may be required to control infections in such cases. In extreme cases, bacterial resistance can be fatal. Antibiotics are powerful bacteria-killing drugs that help our bodies regain the upper hand when a bacterial infection develops. Overuse of broad-spectrum antibiotics, such as second- and third-generation cephalosporins, greatly hastens the development of methicillin resistance.
Staphylococcus aureus a Gram Positive bacterium is one of the examples for ever increasingly resistant pathogens. It is to be found on the mucous membranes and the skin also in healthy people. It is extremely adaptable to antibiotic pressure. Resistant strains, also known by the name Methicillin-resistant Staphylococcus aureus (MRSA), are responsible for difficult-to-treat infections in humans. Since the strains often happen to be resistant to more than one antibiotic compound it may also be referred to as Multiple-Resistant Staphylococcus aureus. 
Over a period of time the bacteria generally develop resistance to antibiotics. Along with the present chemical therapy methods; photodynamic therapy—a treatment method against cancerous cells, has been found to be effective in destroying a wide range of microbes. Photodynamic therapy is based on activation of photosensitizer by appropriate wavelength. Photoactivated photosensitizer generates singlet oxygen and free radicals responsible for destruction of abnormal cells. Various photosensitizers have been studied for their bactericidal effect on pathogenic microbes and were found to be effective.
There are many steps taken to obtain uncontaminated donor's blood, nevertheless the major treat comes from the undetected microbial agents which need to be inactivated before blood transfusion. Blood components can be contaminated during any of the many steps of preparation like blood collection, processing, pooling and transfusion. Thus, tested donor's blood apparently healthy might be contaminated with millions of undetected/unknown infectious microbes. Furthermore, donor's blood units may be contaminated by bacteria during storage which will cause potentially fatal infections in the recipient; or may contain remained leukocytes which then release chemicals causing disease or severe fever.
In U.S. Pat. No. 5,660,731, Piechocki, et al. disclose a method, system and device for removal of methylene blue from biological fluid after anti-microbial treatment. In this patent they disclose a treatment protocol using methylene blue for inactivating materials such as virus and bacteria from blood and blood products. It is also discloses the method of separating the methylene blue from the biological fluid using carbon fibers.
Wollowitz, et al. in his U.S. Pat. No. 6,686,480 discloses how Psoralen compounds are used to form covalent crosslinks to the nuclei acid of pathogen for photo-decontamination of pathogen present in blood.
U.S. Pat. No. 5,545,516 by Wagner discloses methods of inactivating pathogenic contaminant in whole blood, plasma, cellular blood components using phenthiazin-5-ium dye(s) and irradiating at 560-800 nm to inactivate all the pathogens.
In U.S. Pat. No. 7,407,948; Griffiths et al. disclose a photosensitive composition named Phonoselenazinium and its use in photodynamic therapy as anti-infective, anti-cancer and sterilizing agent. In one of the embodiments he discloses the use of this composition for inactivating S. aureus, E. coil and other microbes under in vitro conditions by administering the required dosage of photosensitizer and irradiating the cells, after incubation, with a 665 nm CeramOptec diode laser.
U.S. Pat. No. 6,843,961 (Hlavinka et al.) discloses a PDT method and apparatus for inactivating contaminants in blood and blood products using photosensitizers and light of suitable wavelength.
In U.S. Pat. No. 7,244,841, Love et al. disclose use of a composition for killing or attenuating the growth of microorganisms by a method which does not comprise exposing the composition to photodynamic therapy light or sonodynamic therapy ultrasound source. The stimulation of the compound is innate.
An entirely different and promising approach is phage therapy. Wilson in his US Application Publication No. 2007/0020241 discloses a composition comprising of a photosensitizer and a bacteriophage. The bacteriophage used as targeting agent is staphylophage. The bacteriophages are conjugated to photoactive agents, which then target the bacteria specifically. The invention is useful to inactivate staphylococci, more particularly MRSA, EMSA, VRSA, hetero-VRSA, VISA or CA-MRSA strains. The phage therapy is a more complicated system. In U.S. application no. 2002/0001590 Kelly et al. use bacteriophages with antibacterial agents like antibiotic and chemotherapeutic agents to inactivate the pathogens.
Sowemimo-Coker et al. in U.S. Pat. No. 6,235,508 disclose a method of inactivating viral and bacterial contaminants using a composition having photosensitizers attached to a blocking agent and at least one halogen substituted or one non-hydrogen bonding ionic moiety or both. The preferred two photoactive compounds are psoralen and coumarin which are made to target the nucleic acid of viri specifically and bind to DNA and RNA covalently after irradiation with UV light or ionizing radiation leading to inactivation of the pathogens. The use of low toxic compounds along with PS and ionizing radiation can be harmful. Psoralens, are photoactive DNA-intercalating compounds and do not produce singlet oxygen.
In U.S. Pat. No. 6,323,012 Ben-Hur et al. disclose a PDT method for treating viral infection by administering 5-aminolevulinic acid to viral infected cells. After a short duration red light is applied to photodynamically activate protoporphyrin IX accumulated in viral infected cells.
In U.S. Pat. No. 7,094,378 Goodrich et al. disclose a method and apparatus for treating and inactivating microorganisms present in biological fluids. The method involves adjusting the percentage of plasma in the fluid to be treated and mixing with photosensitizer (riboflavin) and exposing the fluid to light whereby the microbes are inactivated. Similarly Hlavinka et al., in their U.S. Pat. No. 7,077,559 disclose a mixing system, apparatus and method for pathogen reduction in blood and blood products using riboflavin and light. The squeezing or clamping devices ensure proper photo-irradiation of blood and blood components.
Reddy et al in their U.S. Pat. No. 7,049,110 disclose a PDT method and apparatus for inactivating microorganisms in biological fluids by adding non-toxic PS to the fluid and exposing the fluid to photo-irradiation.
The conventional screening and processing methods used against pathogenic microbes are not found to be very effective in controlling its rapid transmission through contaminated blood and blood products. The method disclosed in prior art for elimination of microbes is not found to be effective in attenuating all the bacterial, viral and other pathogens as claimed. Thus, it is essential to eliminate or inactivate these pathogen materials from blood and blood products before transfusion. Unfortunately, up to now there have been many difficulties to eliminate or inactivate blood pathogens in materials from blood or blood products due to insufficient filtration capacity of devices, antibiotic resistance of difficult-to-treat microbes or lack of an efficient and efficacious device and/or method. Thus, there is a need to provide an efficient and efficacious method and device to eliminate or inactivate pathogenic material from blood and blood products, from single donors without damaging the therapeutic and biological properties of such biological fluids.